Recently changed to arcane and just had a question about the effectiveness of charged up.

Given that we cannot pre-click charged up before a pull (arcane charges reset once combat starts), is this really the talent to have for single target dps? Not that the other talents are that great...

Unless I am misunderstanding how to use this talent (likely), analysis of my raid logs highlighted I needed to use this more (not on cooldown enough) but if I already have 4 arcane charges going into evo (which I find is usually the case) there is no need to use it and the rotation in conserve phase of 4 arcane blasts then an arcane barrage... when would I actually use this talent?

Just seems like a gcd that I could be using sonewhere else and just a nice option to have if I need to get 4 AC right away (rather than having it on c/d 90%+ as a target).

It's fantastic for AoE burst, using Barrage -> Charged Up -> Barrage is very strong, and you can use it for damage and mana regen to boot. It plays nicely with Rule of Threes, so you can Barrage -> Charged Up -> Arcane Blast for nearly free, gaining a ton of damage and using almost no mana. Super nice with Equipoise as well if you dropped a touch too low on mana to get some back.

The other options in the row really don't bring much to the table in raids, so Charged Up is the default choice really. Resonance is good for mythic plus trash. Supernova is sadly garbage across the board.

Charged UP is also an awesome filler.
In high movement fights like Blockade, Mekkatorque or Rastakhan, when Blink isn't enough, and you just simply can't wait to clearcasting be procced, you do
Barrage > Charged UP > Barrage
or
Barrage > Charged UP > Arcane Blast
and together with GCD you nicely fill those times you need to move.

Sometimes i use this combo instead of blink, because
Arcane Blast > GCD > Blink > GCD > Arcane Blast
is rather long time without any spell OR i can't blink across the room, for example when in under Pa'ku at Conclave, so i'll do
Arcane Blast > GCD (movement starts) > Arcane Barrage > Charged UP (movement ends) > Arcane Blast
instead

So yeah, even though Charged UP doesn't provide any visible damage boost, it's a very helpful tool in fights where movement is needed.

Charged UP is also an awesome filler.
In high movement fights like Blockade, Mekkatorque or Rastakhan, when Blink isn't enough, and you just simply can't wait to clearcasting be procced, you do
Barrage > Charged UP > Barrage
or
Barrage > Charged UP > Arcane Blast
and together with GCD you nicely fill those times you need to move.

Sometimes i use this combo instead of blink, because
Arcane Blast > GCD > Blink > GCD > Arcane Blast
is rather long time without any spell OR i can't blink across the room, for example when in under Pa'ku at Conclave, so i'll do
Arcane Blast > GCD (movement starts) > Arcane Barrage > Charged UP (movement ends) > Arcane Blast
instead

So yeah, even though Charged UP doesn't provide any visible damage boost, it's a very helpful tool in fights where movement is needed.

When using Shimmer talent - Blink(now shimmer) now has 2 charges, is off the global cooldown, and can be cast while casting. So there is no GCD